do some shadow swings. take the racquet back like we discussed.
make your arm loose.
then make your arm looser.
then as your about to push off and swing forward make your arm looser.
even looser.
make your arm so loose that you can't even feel it. it should feel like it's not even there. like a piece of rope is connected to your shoulder. absolutely zero tension anywhere in your entire arm.
don't take the racquet back too far. do a more compact swing than what you are doing now. like 6 inches less takeback.
then while keeping your arm loose push off right leg and rotate.
don't use your arm at all. absolutely no arm.
just rotate and watch how fast the arm whips around.
it will be faster than your normal swing. even though it may feel weird because you are using NO ARM AT ALL the swing will still look pretty good if you filmed it. and it will be fast even with a regular speed rotation of the body.
do that a few times using no arm.
if you work on getting the racquet at the right angles at the end of the takeback you will find that it will move how you want it to during the forward swing.
Then try to feel the weight of the racquet head. not the racquet. just the weight of the head as you rotate forward. if you are loose and are rotating around the arm will lag and if you didn't take your racquet back too far (disconnected) then you will feel the racquet head tug on your shoulder and chest.

once you feel this pulling then you can use the arm for control. if you don't have this feeling and it feels like you are jerking the racquet or there's an abrupt jolt then your are doing it wrong and maybe takeback is too far.
at this point your chest should be just about facing the net but not quite. you'll be able to use the arm to do isr or pronation or radial dev etc if you want.

just try that. no arm. super loose. just rotate. get used to that feel. if you work on that you'll see your rhs will increase and you'll get ssc w/o thinking about it and your swing will look nice and smooth and whippy.

to do this you need to change your mindset from 'hitting w/ the arm' to 'hitting w/ the body'.
not easy but that's how it's done. you have to be relaxed.

when you swing forward don't go full speed. go slow to medium speed but on the slow side. then when you feel the racquet go backwards and the butt is pointing to the ball then go fast. otherwise your swing won't have the correct shape. it won't resemble a tennis swing at all. so go slow, loose, racquet falls back and head is pointing to back fence, you'll feel this, then accelerate. don't jerk or yank it at this point. just accelerate. as in build up speed. but quickly.

wait. i forgot one thing. i was just trying out those instructions myself.
when you rotate try to lead with the elbow. so make a little bit of tension from the shoulder to the elbow. when you rotation you want the shoulder to the elbow to move together. try to imagine your are leading the swing w/ the elbow. then the elbow goes forward first. that's important. then the racquet head will kind of stay where it is since elbow to hand is very loose. it will stay where it is pretty much then as elbow keeps going forward the racquet head will flip (ssc).

so...
loose, no cocking back the wrist, neutral position setup, rotate, slight tension on upper arm to maintain swing shape.

and you don't have to rotate that fast. just a nice turn. like in that fed cincinnati practice vid. he's doing just what i'm saying here.

Got scared by the elbow flaring up after going back to Tour Bite, so I took a couple of weeks off to rest it. Feels a lot better now! Went bacl to Black Widow with no issues. Will try TB at a lower tension, or maybe hybrid it with something like N.Vy.

Tried not to lean my head over to the right so much, and keep better balance. Also worked on getting the hitting arm looser. I still have a problem when moving to the right.

Playing with Kinovea, and took side by side frames with RF to cement in my mind what I need to do with the takeback. The video was synced to contact point...not sure I chose the right one to compare, I was moving left a bit to take the forehand, but anyway...

1. Still haven't completely gotten rid of the cocked wrist. Racquet head pointed too far back at end of takeback.
2. Forearm partially supinates
3. Balance is off. Footwork needs major work, including my following the rhythm of slower balls. Preparation a bit late.

Having said that, keeping the arm even more relaxed has helped quite a bit, if you watch the videos. More easy power, and the arc of the shot has improved. Feels a LOT better than 2 weeks ago.

Yes, I know. Hard to change, even if I feel I'm doing better, video disproves it. Need to get to the unit turn and just let it drop. I am fantastic at shadow swinging it, but it all goes away on court. I was actually working on that today, shadow swinging with my back to the wall, to try to shorten the backswing and keep the racquet on the right.

Maybe next time I'll put the left hand at the top of the racquet. That'll ensure a PTD. Keep it there till I break the habit.

Just played a set of doubles today. Just focused on contact in front with a loose arm and a shorter backswing. The forehand felt pretty good when hitting, and the ball looked like it had a heavy quality to it, judging from the way it bounced on the other side. Didn't stay at the back too much, so this is the footage I had, including the return of serve.

Slow motion, annotated with where I feel the issue is...I drrew a line where I think I should keep the palm down instead of rotating. I forgot about my great idea of keeping the left hand on the top of the racquet face...http://youtu.be/y7QocsUhdsY

Just played a set of doubles today. Just focused on contact in front with a loose arm and a shorter backswing. The forehand felt pretty good when hitting, and the ball looked like it had a heavy quality to it, judging from the way it bounced on the other side. Didn't stay at the back too much, so this is the footage I had, including the return of serve.

Slow motion, annotated with where I feel the issue is...I drrew a line where I think I should keep the palm down instead of rotating. I forgot about my great idea of keeping the left hand on the top of the racquet face...http://youtu.be/y7QocsUhdsY

Perhaps instead of focusing on your palm, you may want to try and focus on the buttcap of the racquet. (different things resonate with people) In the downswing always "hide the buttcap from the line of the ball. Trust me, when you begin to pull on the racquet, it will "flip" and align properly. In fact, this is one of the keys to maximizing stretch shorten.. the quick internal to external rotation of the arm.

Worked on the takeback and SSC today...after 3 hours of doubles. So please forgive my legs. Concentrated on keeping the backswing short and on my right side. I do think I managed to trim down the takeback and get a somewhat better PTD position, though I suppose I could hide the butt more at the end of the takeback. But at least I'm not getting into the supinated position way before contact!

Well this was taken after about 3 hours of play and 45 minutes of drills, so my legs were shot. Balance is a bit better in the previous video I posted. I would prefer to be able to hit from multiple stances as the situation dictates, but given enough time to set up, I do prefer the semiopen stance. Sometimes I stay too open.

Soderling has too long a swing for me, am trying to shorten it up for easier timing/consistency. The takeback in my last vid struck me as more Agassi than Fed, I think...like here:

Well this was taken after about 3 hours of play and 45 minutes of drills, so my legs were shot. Balance is a bit better in the previous video I posted. I would prefer to be able to hit from multiple stances as the situation dictates, but given enough time to set up, I do prefer the semiopen stance. Sometimes I stay too open.

Soderling has too long a swing for me, am trying to shorten it up for easier timing/consistency. The takeback in my last vid struck me as more Agassi than Fed, I think...like here:

It could help, but it may not. Even with an elevated elbow position, (and i think your's is fine), if the arm rotates externally, the elbow is going to drop and slot, and the racquet head will begin to "lead" back...no bueno. This is the crux of teh problem in your case. You're getting there though.